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A six-mile stretch of the 91 Freeway in Corona was scheduled to close for about 55 hours beginning Friday. Annette Arreola reports for NBC4 Today in LA on Friday, Feb. 19, 2016. (Published Friday, Feb. 19, 2016)

The 91 Freeway in Corona will be completely shut down Friday night, marking the start of a 55-hour closure to accommodate construction activity on the east-west artery.

The shutdown, dubbed "Corona Carmaggedon," will get underway at 9 p.m. between Interstate 15 and the 71 Expressway. Both sides of the 91 will remain closed until 4 a.m. Monday, according to the Riverside County Transportation Commission.

"We had considered performing this work over a series of 20 consecutive night closures, but we know how important it is for Corona commuters to get on the road very early each morning," RCTC Director Anne Mayer said Wednesday.

"By consolidating this work into one weekend, we are able to create a safer working environment for our crews and the motoring public and cut by more than half the amount of anticipated travel delays to the public."

RCTC has been promoting its "91 Steer Clear" campaign since last month to make drivers aware of the closure and how to prepare.

"Safety is the number one priority, and Caltrans is working with all the agencies involved to keep the `91 Steer Clear' closure safe for the motoring public and the workers," Caltrans District 8 Director John Bulinski said.

During the closure, all westbound traffic attempting to transit the 91through Corona will be diverted onto Interstate 15, and all eastbound vehicles will be detoured onto the 71 expressway.

Officials anticipated major backups on the 15 and the 71, as well as on surface streets in Riverside and west Corona. Riverside officials have warned of lengthy travel delays throughout the west end of the city, particularly along La Sierra Avenue and Pierce Street.

Commuters trying to go east or west via inland or Orange County freeways were encouraged to use Interstate 10, state Route 60 or state Route 210 through the weekend.

Mayer predicted the 15, 71 and 91 freeways will be clogged around the closure zone, with delays stretching three to four hours.

CHP officers, Riverside County sheriff's deputies, as well as Riverside and Corona police officers will be out in force for traffic control and to respond to emergencies during the shutdown.

CHP Capt. Kevin Porter said that the agency will be coordinating with Caltrans and Corona to handle traffic jams and move first responders quickly around backups, using closed portions of the 91 whenever necessary.

"Staff can dispatch emergency responders to problems, send tow trucks, adjust traffic signals remotely, and work hand-in-hand with Caltrans to post travel information and other updates to the overhead message signs around the region," Porter said.

Mayer said the westbound side of the Maple Street bridge at the 91 will be demolished, and crews will install support beams at the flyover ramp connected to the bridge, as well as pave a portion of the eastbound 91 under Interstate 15. Several mini projects will also take place, such as filling potholes, painting K-rails and patching ramps and bridges along the heavily used corridor.

Mayer said the shutdown will not settle all construction needs, noting that future overnight closures will be necessary at various locations in the project area -- though nothing approaching the magnitude of this weekend.

The $1.3 billion 91 expansion project, which got underway in early 2014, involves widening the east-west corridor between the Orange County line and I- 15, with new traffic lanes and ramps, as well as additional shoulder space and enlarged surface streets in the vicinity of the freeway.